Natural gemstones, such as diamonds have been mined for centuries. The raw mined diamond may be irregularly shaped, and may be cut to optimize the size and shape of a finished gemstone. Much skill goes into selecting the cut of a raw stone and the actual process of cutting the stone to a desired shape.
In natural or high temperature, high pressure manufactured stones, the yield of the gemstone into finished cut stone is dictated by the shape and orientation of the unfinished stone, which can range from perfect crystals to irregular shapes. This results in an average yield of gemstones of less than 50 percent and usually about 30%.